WEEK 7 RADIATION BIOLOGY

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WEEK 7RADIATION BIOLOGY PROTECTION Part 1

• FINAL

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Sources of Ionizing Radiation

1. ___________ Radiation
2. ___________Radiation

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Electromagnetic Spectrum shows ranges in
intensity
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Background Radiation has been around a long time.
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Radon Uranium most common sources
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AVE population exposure 20 30
mrem/year

• In some places in
• United States average ________mrem/yr
• Majority due to _________ gas  
• Many places on earth
• receive more than _________ mrem/yr from radon

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MEDICAL IMAGING

• __________________x-rays
• _________________ x-rays
• Greatest source of
• ________ ________radiation

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What is the difference between x-rays and gamma
rays????

• Their______________________
• X-rays are _______ __________
• Gamma comes from the ______
• of the atom

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Terminology to cover

1. Units of Measurement
2. ALARA
3. DOSE
4. Cumulative
5. Annual
6. Target theory
7. Direct vs. Indirect Hit
8. Somatic vs. genetic

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UNITS OF RADIATION MEASUREMENT

• To ______________the amount of radiation
• A Received by
• _________________
• _________________
• _________________

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Conventional vs. SI units

1. New system developed in 1948
2. System of Units based on Metric measurements
   developed by International Committee for Weights
   and Measures
3. 1985- officially adopted

1. British units used since 1920s
2. United States still uses this system

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Conv. Units SI Units

1. RADS
2. REMS
3. R - ROENTGEN

1. _______
2. _______
3. _______

Not equal in amount
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Comparsion of Units
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REMS OCCUPATIONAL EXPOSURE
R - ROENTGENS
RADS PATIENT DOSE
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Conventional Unit of ROENTGEN (R)

1. SI unit __________
2. The quantity of radiation exposure
   in_______________
3. Measures __________of the x-ray tube
4. Does not indicate the actual _____________________
   ___________

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RADIATION ABSORBED DOSE (RAD) SI
GRAY (Gy)

1. Measures the _____________ of energy ___________
   by any medium (__________)
2. 1 Gray (Gy) 100 _______
3. 1/100 Gy 1 _______

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RAD to GRAY

• 100 rad 1 Gy 1000 mGy
• 1/100 Gy 1 rad
• 10 rad .1 Gy 100 mGy
• 1000 mRad 1 rad .01 Gy 10 mGy

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Radiation Equivalent Man

• Used for ________
• Traditional Unit _________
• SI Unit ____________ (Sv)
• 1 Sv 100 __________
• 1/100 Sv 1 _________

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RADIATION EQUIVALENT MAN(REMS) SI UNITS
SIEVERT

• Different _________ of radiation produce
  different responses
• The unit of dose ___________, expressed as
• __________________________________
• Used for ____________(employee) exposures
• Can be used when for dose of patient

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QUALITY FACTOR

• Qualifies what the damage is from
• different types of radiation
• Example QF for X-ray is 1
• QF for alpha is 20
• Alpha is 20 x more damaging to tissue

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Rad VS. Rem

• QF of x-ray is 1
• 1 RAD X QF 1 REM
• 1 GRAY X QF 1 SIEVERT

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Why did the bunny die??

• BUNNY A
• Received 200 rads

• BUNNY B
• Received 200 rads

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Why did the bunny die??

• BUNNY A
• 200 rads x 1 for
• X-RAY 200 RADS

• BUNNY B
• 200 rads x 20 for alpha
• 4000 rads

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REM to Sievert

• 100 rem 1 sV 1000 msv
• 10 rem .1 sV 100 msv
• 1000 mRem 1 rem .01 sV 10 msv

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RADS REMS

• RADS
• GRAYS
• Patient absorbed dose

• REMS
• SIEVERTS
• Employee
• (technologists)

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Cell Response to Radiation
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Response of cells to radiation

• Cell sensitivity is dependant on
• Type of cell
• Type of damage received
• Type of radiation exposed to

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Sensitivity to radiation based on sex
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Which (Male or Female) GONADs are external vs
internal?
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Which gender has gonads from birth?
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Which gender constantly produces new reproductive
cells?
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Which GENDER is more sensitive to radiation at
birth? Why?
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Dose limits
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Permissible Occupational Dose

• Annual dose
• 5 Rem/year 50mSv/year
• (5000 mrem)
• Cumulative Dose
• 1 rem x age 10mSv x age

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Allowable DOSE - ANNUAL

• BRITISH UNIT
• 5 REMS

• SI UNIT
• 5O mSv

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OCCUPATIONAL EXPOSURES

• 5 REMS / YEAR
• BUT NOT TO EXCEED 1.25 REM/QUARTER

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Allowable DOSE TOTALCUMMULATIVE

• SI UNIT
• Age x 10msv

• BRITISH UNIT
• Age x 1 rem
• Old MPD dose 5(age-18)

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Declared Pregnant Worker

• ____ badges provided
• 1 worn at collar (___________________exposure)
• 1 worn inside apron at waist level (____
  exposure)
• Under 5 rem _____________________ risk
• Risk _____________________ above 15 rem
• Recommend ________ (spontaneous) 25 rem
• (Baby exposure approx 1/1000 of ESE)
• www.ntc.gov/NRC/RG/08/08-013.html

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Pregnancy Embryo

• Mother __________worker
• (5 rem)
• Baby
• 500_______.5 rem/ year
• .05 rem/____________
• 5______
• .5 mSv / ________

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Fetus Exposure

• Radiation exposure is most harmful during the
  __________ trimester of pregnancy
• ______________ Exposure limit
• 0.05 rem or 0.5 mSv PER MONTH
• 0.5 rem or 5 mSv total gestation

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Education and Training Exposures

• Students must never hold patients during
  exposures
• Effective dose limit (Annual)
• 0.1 rem or 1 mSv
• (1/50 of Technologists dose)

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PUBLIC EXPOSURE NON MEDICAL EXPOSURE

• 10 of Occupational exposure
• 0.5 rad or 500 mrad or 50mgray
• Under age 18 and Students
• 0.1 rem 10 mrem 1mSv

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Review
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Radiation Monitoring
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Radiation Monitoring

1. Monitors measure the quantity of radiation
   received.
2. Any radiation worker must be monitored
3. to determine estimated dose exposure

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Personnel Monitoring Devices

1. Film Badges
2. Thermoluminescent Dosimeters (TLD)
3. Pocket Dosimeters
4. Optically Stimulated Luminescence (OSL Dosimeters)

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TLD
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Film Badges changed monthly
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POSL
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Field Survey Instruments

• Cutie Pie
• Ionization Chamber

• Geiger Muller counter

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Q t x ?
CUTIE PIE
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Review

• What is the annual allowable dose for a 32 year
  old Technologist?

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• What is the cummulative allowable dose for a 32
  year old Technologist?

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Regulatory Agencies

• NCRP
• National Council on Radiation Protection
• NRC
• Nuclear Regulatory Committee

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REGULATORY AGENCIES

• NCRP - Reviews recommendation for radiation
  protection safety.
• Distributes information re radiation awareness
• NRC
• Makes LAWS enforces regulations

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QUESTIONS ?